β-Diketone and hydrotalcite stabilizer compositions for halogen-containing polymers and polymer compositions containing the same

ABSTRACT

Stabilizer compositions for halogen-containing polymers are provided composed of a β-diketone as well as metal and organotin enolate salts thereof; and a hydrotalcite having the general formula: 
     
         Mg.sub.1-x Al.sub.x (OH).sub.2 A.sub.x/2.mH.sub.2 O 
    
     wherein 
     x is a number from 0 to 0.5; 
     A is CO 3   =   or SO 4   = , and 
     m is a number representing the number of H 2  O in the molecule. 
     The stabilizer compositions are effective in enhancing the resistance to deterioration by heat and light of halogen-containing polymers and especially polyvinyl halide resins. The β-diketone and hydrotalcite in these compositions exhibit a synergistic stabilizing effectiveness superior to either alone in like amount.

This is a continuation-in-part of Ser. No. 319,815 filed Nov. 9, 1981, now abandoned.

Halogen-containing resin degrade with discoloration and deterioration in mechanical strength during heat processing. Therefore, various kinds of heat stabilizers have been added to inhibit such deterioration. However, many conventional stabilizers depreciate the desirable electrical properties of the resin, so that they cannot be used for electrical cable and wire insulation compositions.

Lead stabilizers such as tribasic lead sulfate have been used for cable and wire insulation, but lead stabilizers have fallen into disfavor because of their toxicity.

Hydrotalcites are proposed as stabilizers for polyvinyl chloride in Japanese patent publication Kokai No. 80445/80. Hydrotalcites are pearly-white minerals, usually

    Mg.sub.6 Al.sub.2 (OH).sub.16 (CO.sub.3).4H.sub.2 O

but also of variable composition

    Mg.sub.x Al.sub.y (OH).sub.2 (CO.sub.3).sub.z.sbsb.2.nH.sub.2 O

consisting of hydrous aluminum and magnesium hydroxide and carbonate CO₃ ⁼ or sulfate SO₄ ⁼.

However hydrotalcites add their own color to the resin, and heat stability and electrical properties are still insufficient.

The combination of β-diketones with basic metal inorganic acid salts was proposed in Japanese publication Kokai No. 62250/79. However, this combination is insufficient.

β-Diketones are known stabilizers for halogen-containing resins.

J. Darby, U.S. Pat. No. 2,669,548, patented Feb. 16, 1954, discloses halogen-containing resin compositions having improved stability containing a mixture of a zinc salt and a calcium chelate derivative of a 1,3-dicarbonylic compound.

F. Ebel, U.S. Pat. No. 3,001,970 patented Sept. 26, 1961, discloses preventing the discoloration of vinylidene chloride polymers by light by adding a small amount of dibenzoyl methane.

British Pat. No. 1,141,971 of May 23, 1967 to W. R. Grace & Co. discloses zinc complexes of beta-dicarbonyl compounds, used as stabilizing additives for chlorine-containing polymers.

L. Weisfeld, U.S. Pat. No. 3,493,536, patented Feb. 3, 1970, discloses that diaroylmethane compounds provide stabilizing action against the sensitizing effect of bismuth or antimony compounds on chlorine-containing materials.

M. Crochemore, U.S. Pat. No. 4,102,839, patented July 25, 1978, discloses the possibility of preventing the thermal breakdown of vinyl chloride polymers by adding one or more metal salts and a 1,3-dicarbonyl compound.

M. Gay, U.S. Pat. Nos. 4,123,399 and 4,123,400, patented Oct. 31, 1978, discloses vinyl chloride compositions containing metal salts, polyol and a 1,3-dicarbonyl compound.

1,3-Diketones are known that contain carboxy or ester groups, but not as vinyl chloride polymer stabilizers. 1,3-Dicarbonyl compounds containing carboxy or ester groups can be prepared by the base-catalyzed condensation reaction of a diester of benzene dicarboxylic acid with a ketone (see, for example, B. T. Brown et al, Pestic. Sci. 1973, 473-484) or by reaction of a carboxy acetophenone with a carboxylic ester (see, for example, H. Imai et al, Nippon Kagaku Kaishi 1977 1081).

In accordance with the present invention, stabilizer compositions for halogen-containing polymers are provided composed of a β-diketone having the formula: ##STR1## wherein: R₁ is selected from the group consisting of hydrogen, hydrocarbon groups having from one to about eighteen carbon atoms and such groups substituted with one or more groups selected from the group consisting of halogen, hydroxy, alkoxy OR₁, ester COOR₁, alkyl and alkoxycarbonyl alkyl having from one to about eighteen carbon atoms, and ##STR2## R₂ is selected from the group consisting of hydrogen; hydroxyl; hydrocarbon having from one to about eighteen carbon atoms and such hydrocarbon groups substituted with one or more groups selected from the group consisting of halogen, hydroxy, alkoxy OR₁, ester COOR₁, alkyl and alkoxycarbonyl having from one to about eighteen carbon atoms; and if Z is R₂ or n is 1 to 3, then no more than one R₂ is hydrogen;

one R₁ and one R₂ or two R₂ may be linked together as an alkylene group to form a cyclic ring structure;

n is a number selected from 0 to 3; and

Z is selected from the group consisting of R₂ and a polyvalent linking radical selected from the group consisting of a direct linkage between the ##STR3## polyvalent hydrocarbon R₃ ; ##STR4## wherein: R₃ is a polyvalent hydrocarbon group having from one to about eighteen carbon atoms;

R₄ and R₅ are selected from the group consisting of hydrogen and hydrocarbon groups having from one to about eighteen carbon atoms; and R₄ and R₅ may be linked together as an alkylene to form a cyclic or ring structure;

X is --O-- or --S--;

m is 0 or 1; and

R₆ is selected from the group consisting of hydrogen, hydrocarbon having from one to about eighteen carbon atoms, and --R₃ --;

as well as metal and organotin enolate salts thereof; and a hydrotalcite having the general formula:

    Mg.sub.1-x Al.sub.x (OH).sub.2 A.sub.x/2.m.sub.1 H.sub.2 O

wherein

x is a number from 0 to 0.5;

A is CO₃ ⁼ or SO₄ ⁼, and

m₁ is a number representing the number of H₂ O in the molecule.

The stabilizer compositions are effective in enhancing the resistance to deterioration by heat and light of halogen-containing polymers and especially polyvinyl halide resins. The β-diketone and hydrotalcite in these compositions exhibit a synergistic stabilizing effectiveness superior to either alone in like amount.

The β-diketone is employed in an amount within the range from about 0.001 to about 5 parts, preferably from 0.005 to 1 part, per 100 parts by weight of the polymer.

The hydrotalcite is employed in an amount within the range from about 0.01 to about 10 parts, preferably from 0.05 to 5 parts, per 100 parts of the polymer.

The β-diketone compounds also exist in the equilibrium forms of metal and organotin enolate salts of one or more (in admixture) of the various enol forms exemplified by the species: ##STR5##

The metal as in other enolate salts replaces one or more hydrogens of the enol hydroxyl, according to the valence of the metal, producing various enolate salts exemplied by the forms: ##STR6## which salts are accordingly represented generically herein by the formula: ##STR7## it being understood that one hydrogen is replaced by M at one enol group.

n represents the valence of M. M is any metal, monovalent or polyvalent, preferably a metal conventionally used in metal salt stabilizers for polyvinyl chloride resins, such as lithium, sodium, potassium, magnesium, strontium, barium, calcium, cadmium, lead, zinc, aluminum, antimony, tin or zirconium, as well as organotin (R)_(m1) Sn where m₁ is one, two or three, and R is a hydrocarbon group having from one to about eighteen carbon atoms.

The tautomeric equilibrium between form I and forms II and III can be represented as follows:

For the monovalent metal salts M, the equilibrium becomes: ##STR8##

For polyvalent metal salts, the 1,3-dicarbonyl radical is multiplied according to the valence of M.

All forms of β-diketones of this invention are effective in stabilizing polyvinyl halide resins. When M is a metal, while numerous structural formulae can be written, differing in the location of metal in the enolate, all are equivalent, and therefore the formula is better represented as a hybrid of all formulae than any single one.

The M organotin group has from one to three hydrocarbon groups R linked to tin through carbon. Each hydrocarbon group R linked to carbon can have from one to eighteen carbon atoms. The hydrocarbon groups R include alkyl, cycloalkyl, aryl, and alkylaryl groups. The R group can also be substituted with one or more ester groups COOR₂. Alkyl groups and alkoxycarbonyl alkyl groups are preferred.

Exemplary R groups include methyl, butyl, hexyl, octyl, isooctyl, 2-ethyl hexyl, nonyl, decyl, stearyl; cyclohexyl, cyclopentyl, cycloheptyl; phenyl, benzyl, phenethyl, naphthyl; methoxycarbonylethyl, ethoxycarbonylmethyl, and butoxycarbonylethyl.

The total of the number of organic groups R linked to tin through carbon plus the number of β-diketone groups is:

    ______________________________________                                                                    Di-      Tri-                                                      Monoorganotin                                                                              organotin                                                                               organotin                                  Type of organotin group                                                                       RSn         R.sub.2 Sn                                                                              R.sub.3 Sn                                 ______________________________________                                         Number of β-diketone                                                                     3           2        1                                          groups                                                                         ______________________________________                                    

The organic groups R linked to tin through carbon can be the same or different.

Representative organotin groups include monomethyltin, mono-n-butyltin, monoisobutyltin, mono-2-ethylhexyltin, methoxycarbonylethyltin; dimethyltin, di-n-butyltin, di(ethoxycarbonylethyl)tin, methyl-n-octyltin, n-butyl-n-butoxycarbonylethyltin, di-n-octyltin; tri(methoxycarbonylethyl)tin, tri-n-octyltin, and methyl di(2-ethylhexyloxycarbonylethyl)tin.

The hydrocarbon groups R₁, R₂ and R₃ can be open chain or cyclic, and include such aliphatic, cycloaliphatic and aromatic hydrocarbon groups as alkyl groups having from one to about eighteen carbon atoms; cycloalkyl, cycloalkylalkylene, and alkylcycloalkyl groups having from five to about eighteen carbon atoms; and aryl groups (including aralkyl and alkaryl groups) having from six to about eighteen carbon atoms; for example, methyl, ethyl, propyl, ispropyl, butyl, isobutyl, sec-butyl, tert-butyl, amyl, tert-amyl, tert-hexyl, tert-heptyl, iso-heptyl, tert-octyl, 2,4,4-trimethylpentyl, 2-ethylhexyl, iso-octyl, nonyl, decyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl; 1-methylcyclopentyl, cyclohexyl, cycloheptyl; phenyl, naphthyl, tetralinyl; methylphenyl, ethylphenyl, butylphenyl, t-butylphenyl, octylphenyl, nonylphenyl, dimethylphenyl, benzyl and phenethyl.

Substituted hydrocarbon R₁, R₂ and R₃ groups include trifluoromethyl, trichloromethyl, hydroxyheptadecyl, methoxyethyl, hydroxyphenyl, methoxyphenyl, methylenedioxyphenyl, carbomethoxyphenyl and chlorophenyl.

Particularly preferred β-diketones represented by the above general formulae according to the invention include the compounds shown below, as well as their enol tautomers, and metal enolates and organotin enolates: ##STR9##

These compounds can be named as follows:

1. Dehydroacetic acid.

2. Dehydropropionylacetic acid.

3. Dehydrobenzoyl acetic acid.

4. Cyclohexane-1,3-dione.

5. Dimedone.

6. 2,2'-Methylenebiscyclohexane-1,3-dione.

7. 2-Benzylcyclohexane-1,3-dione.

8. Acetyltetralone.

9. Palmitoyltetralone.

10. Stearoyltetralone.

11. Benzoyltetralone.

12. 2-Acetylcyclohexanone.

13. 2-Benzoylcyclohexanone.

14. 2-Acetyl-cyclohexane-1,3-dione.

15. Benzoyl-p-chlorobenzoylmethane.

16. Bis-(4-methylbenzoyl)methane.

17. Bis-(2-hydroxybenzoyl)methane.

18. Benzoylacetone.

19. Tribenzoylmethane.

20. Diacetylbenzoylmethane.

21. Stearoylbenzoylmethane.

22. Palmitoyl benzoylmethane.

23. Lauroyl benzoylmethane.

24. Dibenzoylmethane.

25. 4-Methoxybenzoylbenzoylmethane.

26. Bis-(4-methoxybenzoyl)methane.

27. Bis-(4-chlorobenzoyl)methane.

28. Bis-(3,4-methylenedioxybenzoyl)methane.

29. Benzoylacetyl octylmethane.

30. Benzoyl acetyl phenylmethane.

31. Stearoyl-4-methoxy-benzoylmethane.

32. Bis-(4-t-butylbenzoyl)methane.

33. Butanoyl acetone.

34. Heptanoylacetone.

35. Distearoylmethane.

36. Acetylacetone.

37. Stearoylacetone.

38. Palmitoylacetone.

39. Lauroylacetone.

40. Benzoylformylmethane.

41. Benzoyl phenylacetyl methane.

42. Bis-(cyclohexanoyl)methane.

43. Di-pivaloyl methane.

Exemplary metal salts of the above β-diketone compounds that can be employed in this invention include the Li, Na, K, Mg, Ca, Ba, Sr, Zn, Al, Zr and Sn salts.

The hydrotalcites include the various naturally occuring mineral hydrotalcites and synthetic hydrotalcites falling within the above-described formula: Mg_(1-x) Al_(x) (OH)₂ A_(x/2).mH₂ O. They can be used in the form of their higher fatty acid alkali metal salts or organic sulfonic acid alkali metal salts.

The stabilizer compositions of the invention are effective in enhancing the resistance to deterioration by heat and light of any halogen-containing polymers. They are especially effective with polyvinyl halide resins. The term "polyvinyl halide" as used herein is inclusive of any polymer formed at least in part of the recurring group: ##STR10## and having a halogen content in excess of 40%. In this group, X is halogen; fluorine, chlorine or bromine, and the X₂ groups can each be either hydrogen or halogen, and n is the number of such units in the polymer chain. In polyvinyl fluoride, polyvinyl chloride and polyvinyl bromide homopolymers, each of the X₂ groups is hydrogen. Thus, the term includes not only polyvinyl fluoride, polyvinyl chloride and polyvinyl bromide homopolymers, but also afterhalogenated polyvinyl halides as a class, for example, the afterchlorinated polyvinyl chlorides disclosed in British Pat. No. 893,288, and also polyvinylidene chloride, chlorinated polyethylene, chlorinated polypropylene, chlorinated rubber and copolymers of vinyl fluoride, vinyl chloride or vinyl bromide in a major proportion and other copolymerizable monomers in a minor proportion, such as copolymers of vinyl chloride and vinyl acetate, copolymers of vinyl chloride with acrylic or maleic or fumaric acids or esters, such as acrylic acid ester, maleic acid ester, methacrylic acid ester and acrylonitrile, and copolymers of vinyl chloride with styrene, ethylene, propylene, isobutene, vinylidene chloride, butadiene, isoprene; terpolymers of vinylchloride, styrene and acrylonitrile. The 1,3-dicarbonyl compounds are effective also with mixtures of polyvinyl halide in a major proportion with a minor proportion of other synthetic resins such as chlorinated polyethylene or a terpolymer of acrylonitrile, butadiene and styrene.

The stabilizer compositions are applicable to the stabilization of rigid polyvinyl fluoride, polyvinyl chloride and polyvinyl bromide resin compositions, that is, polyvinyl halide resin compositions which are formulated to withstand high processing temperatures, of the order of 375° F. and higher, as well as plasticized polyvinyl halide resin compositions of conventional formulation, even though resistance to heat distortion is not a requisite. Conventional plasticizers well known to those skilled in the art can be employed such as, for example, dioctyl phthalate, octyl diphenyl phosphate and epoxidized soybean oil.

Particularly useful plasticizers are the epoxy higher esters having from 20 to 150 carbon atoms. Such esters will initially have had unsaturation in the alcohol or acid portion of the molecule, which is taken up by the formation of the epoxy group.

Typical unsaturated acids are acrylic, oleic, linoleic, linolenic, erucic, ricinoleic, and brassidic acids, and these may be esterified with organic monohydric or polyhydric alcohols, the total number of carbon atoms of the acid and the alcohol being within the range stated. Typical monohydric alcohols include butyl alcohol, 2-ethyl hexyl alcohol, lauryl alcohol, isooctyl alcohol, stearyl alcohol, and oleyl alcohol. The octyl alcohols are preferred. Typical polyhydric alcohols include pentaerythritol, glycerol, ethylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, neopentyl glycol, ricinoleyl alcohol, erythritol, mannitol and sorbitol. Glycerol is preferred. These alcohols may be fully or partially esterified with the epoxidized acid. Also useful are the epoxidized mixtures of higher fatty acid esters found in naturally-occurring oils such as epoxidized soybean oil, epoxidized olive oil, epoxidized coconut oil, epoxidized cottonseed oil, epoxidized tall oil fatty acid esters and epoxidized tallow. Of these, epoxidized soybean oil is preferred. Also useful are epoxidized polybutadiene, methyl- butyl- or 2-ethylhexyl epoxy stearate, tris(epoxypropyl) isocyanurate, epoxidized castor oil, epoxidized safflower oil, 3-(2-xenoxy)-1,2-epoxypropane, Bisphenol A-polyglycidylether, vinylcyclohexene-di-epoxide, dicyclopentadiene di-epoxide and 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate.

The alcohol can contain the epoxy group and have a long or short chain, and the acid can have a short or long chain, such as epoxystearyl acetate, epoxystearyl stearate, glycidyl stearate, and polymerized glycidyl methacrylate.

The polyvinyl halide resin can be in any physical form, including, for example, powders, films, sheets, molded articles, foams, filaments, and yarns.

A sufficient amount of the stabilizer composition is used to enhance the resistance of the polyvinyl halide to deterioration in physical properties, including, for example, discoloration and embrittlement, under the heat and/or light conditions to which the polymer will be subjected. Very small amounts are usually adequate. Amounts within the range from about 0.01 to about 15% by weight of the polyvinyl halide resin are satisfactory. Preferably, an amount within the range from about 0.1 to about 5% is employed, for optimum stabilizing effectiveness.

The stabilizer compositions of the invention can be employed as the sole stabilizers. They can also be used in combination with other conventional heat and light stabilizers for polyvinyl halide resins, in which combinations they show a further synergistic interaction, and provide a further enhanced effectiveness, such as, for example, monovalent and polyvalent metal salts, alkaline earth metal phenolates, organic phosphites, and phenolic antioxidants, as well as 1,2-epoxy compounds, organotin compounds, thioethers, and ultraviolet light stabilizers.

The metal salts of carboxylic acids can be alkali metal salts, such as the lithium, sodium and potassium salts. The metal salt can be used in an amount within the range from about 0.01 to about 5 parts per 100 parts by weight of polymer.

The polyvalent metal salts can be salts of any metal of Group II of the Periodic Table, such as zinc, calcium, cadmium, barium, magnesium and strontium, as well as tin, aluminum, zirconium and antimony.

The organic acid will ordinarily have from about six to about twenty-four carbon atoms, and can be any organic non-nitrogenous monocarboxylic acid. The aliphatic, aromatic, alicyclic and oxygen-containing heterocyclic organic acids are operable as a class. By the term "aliphatic acid" is meant any open-chain carboxylic acid, substituted, if desired, with nonreactive groups, such as halogen, sulfur and hydroxyl. By the term "alicyclic" it will be understood that there is intended any cyclic acid in which the ring is nonaromatic and composed solely of carbon atoms, and such acids may if desired have inert, nonreactive substituents such as halogen, hydroxyl, alkyl radicals, alkenyl radicals and other carbocyclic ring structures condensed therewith. The oxygen-containing heterocyclic compounds can be aromatic or nonaromatic and can include oxygen and carbon in the ring structure, such as alkyl-substituted furoic acid. The aromatic acids likewise can have nonreactive ring substituents such as halogen, alkyl and alkenyl groups, and other saturated or aromatic rings condensed therewith.

As exemplary of the acids which can be used in the form of their metal salts there can be mentioned the following: hexoic acid, 2-ethylhexoic acid, n-octoic acid, isooctoic acid, pelargonic acid, neodecanoic acid, capric acid, undecylic acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, 12-hydroxystearic acid, oleic acid, ricinoleic acid, erucic acid, behenic acid, chlorocaproic acid, hydroxy capric acid, benzoic acid, phenylacetic acid, butyl benzoic acid, ethyl benzoic acid, isopropyl benzoic acid, hexyl benzoic acid, salicylic acid, 5-t-octyl salicylic acid, naphthoic acid, 1-naphthalene acetic acid, orthobenzoyl benzoic acid, naphthenic acids derived from petroleum, abietic acid, dihydroabietic acid, hexahydrobenzoic acid, and methyl furoic acid, as well as partially esterified dibasic acids such as monobutylphthalate, isooctylmaleate and 2-ethoxyethyl maleate.

The water-insoluble salts are preferred, because they are not leached out when the plastic is in contact with water. Where these salts are not known, they are made by the usual types of reactions, such as by mixing the acid, or anhydride with the corresponding oxide or hydroxide of the metal in a liquid solvent, and heating, if necessary, until salt formation is complete.

Instead of or together with the above metal salts of organic acids, a metal salt of a phenol or hydrocarbon-substituted phenol can be used in an amount within the range from about 0.01 to about 15% by weight of the polyvinyl halide resin. Preferably, an amount within the range from about 0.1 to about 5% is empolyed, for optimum stabilizing effectiveness. Among such metal phenolates there can be mentioned salts of any of the above monovalent and polyvalent metals with phenol, cresol, ethylphenol, xylenol, butylphenol, isoamylphenol, isooctylphenol, t-nonylphenol, decylphenol, dodecylphenol, t-octylphenol, cyclohexylphenyl, di-t-nonylphenol, methyl isohexyl phenol, phenylphenol.

A variety of organic triphosphites and acid phosphites can be employed, of which the following are exemplary. The phosphite can be used in an amount within the range from about 0.01 to about 15% by weight of the polyvinyl halide resin. Preferably, an amount within the range from about 0.1 to about 5% is employed, for optimum stabilizing effectiveness.

The organic triphosphite can be any organic phosphite having three or more organic radicals attached to phosphorus through oxygen. The acid phosphite can be any organic phosphite having one or two organic radicals attached to phosphorus through oxygen. These radicals can be monovalent radicals, in the case of the triphosphites, diphosphites and monophosphites.

The organic triphosphites in which the radicals are monovalent radicals can be defined by the formula: ##STR11## in which R₁, R₂ and R₃ are selected from the group consisting of alkyl, alkenyl, aryl, alkaryl, aralkyl, and cycloalkyl groups having from one to about thirty carbon atoms.

The acid phosphites are defined by the same formula, but one or two of R₁, R₂ and R₃ is hydrogen or a cation of a metal or ammonium.

Also included are the organic triphosphites having a bivalent organic radical forming a heterocyclic ring with the phosphorus of the type: ##STR12## in which R₄ is a bivalent organic radical selected from the group consisting of alkylene, arylene, aralkylene, alkarylene and cycloalkylene radicals having from two to about thirty carbon atoms, and R₅ is a monovalent organic radical as defined above in the case of R₁, R₂ and R₃.

R₅ is hydrogen or a cation, in the case of the acid phosphites.

Also useful organic triphosphites are mixed heterocyclic-open chain phosphites of the type: ##STR13##

More complex triphosphites are formed from trivalent organic radicals, of the type: ##STR14## in which R₆ is a trivalent organic radical of any of the types of R₁ to R₅, inclusive, as defined above.

A particularly useful class of complex triphosphites are the tetraoxadiphosphaspiro undecanes of the formula: ##STR15## where R₁ and R₂ are selected from the group consisting of aryl, alkyl, aryloxyethyl, alkyloxyethyl, aryloxyethoxyethyl, alkyloxyethoxyethyl and alkyloxypolyethoxyethyl having from about one to about thirty carbon atoms.

In the case of the acid phosphites, one or both of R₁ and R₂ is also hydrogen or a cation.

An especially preferred class of organic triphosphites and acid phosphites have a bicyclic aromatic group attached to phosphorus through oxygen, with no or one or more phenolic hydroxyl groups on either or both of the aromatic rings. These phosphites are characterized by the formula: ##STR16## in which Ar is a mono or bicyclic aromatic nucleus and m is an integer of from 0 to about 5. Z is one or a plurality of organic radicals as defined above for R₁ to R₆, taken singly or together in sufficient number to satisfy the valences of the two phosphite oxygen atoms.

One or both Z radicals is also hydrogen, in the case of the acid phosphites, and can include additional bicyclic aromatic groups of the type (HO)_(m) --Ar.

The cation in the case of acid phosphites can be a metal, such as an alkali metal, for instance, sodium, potassium or lithium; an alkaline earth metal, for instance, barium, calcium, or a nontoxic polyvalent metal, such as magnesium, tin and zinc.

Usually, the triphosphites and acid phosphites will not have more than about sixty carbon atoms.

Exemplary triphosphites are monophenyl di-2-ethylhexyl phosphite, diphenyl mono-2-ethylhexyl phosphite, diisooctyl monotolyl phosphite, tri-2-ethylhexyl phosphite, phenyl dicyclohexyl phosphite, phenyl diethyl phosphite, triphenyl phosphite, tricresyl phosphite, tri(dimethylphenyl)phosphite, trioctadecyl phosphite, triisooctyl phosphite, tridodecyl phosphite, isooctyl diphenyl phosphite, diisooctyl phenyl phosphite, tri(t-octylphenyl)phosphite, tri(t-nonylphenyl)phosphite, benzyl methyl isopropyl phosphite, butyl dicresyl phosphite, isooctyl di(octylphenyl)phosphite, di(2-ethylhexyl) (isooctylphenyl)phosphite, tri(2-phenyl)phosphite, ethylene phenyl phosphite, ethylene isohexyl phosphite, ethylene isooctyl phosphite, ethylene cyclohexyl phosphite, 2-phenoxy-5,5-dimethyl-1,3,2-dioxaphosphorinane, 2-butoxy-1,3,2-dioxyphosphorinane, 2-octoxy-5,5-dimethyldioxaphosphorinane, and 2,-cyclohexyloxy-5,5-diethyl dioxaphosphorinane.

Exemplary pentaerythritol triphosphites are 3,9-diphenoxy-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane (diphenyl-pentaerythritol-diphosphite),3,9-di(decyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro (5,5)-undecane, 3,9-di(isodecyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane, 3-phenoxy-9-isodecyloxy-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane, 3,9-di(methoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane, 3,9-di(lauryloxy)-2,4,8,10-tetra oxa-3,9-diphosphaspiro-(5,5)-undecane, 3,9-di-p-tolyloxy-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane; 3,9-di(methoxyethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane; 3-methoxyethyloxy-9-isodecyloxy-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane; 3,9-di(ethoxyethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane; 3,9-di(butoxyethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane; 3-methoxyethyloxy-9-butoxyethyloxy-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane; 3,9-di(methoxyethoxyethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane; 3,9-di(butoxyethoxyethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane; 3,9-di(methoxyethoxyethoxyethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane; 3,9-di(methoxy(polyethoxy)ethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane (where the (polyethoxy)ethyloxy group has an average molecular weight of 350) 3,9-di(methoxy(polyethoxy)ethyloxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane (where the (polyethoxy)ethyloxy group has an average molecular weight of 550).

Exemplary of the bis aryl triphosphites are: bis(4,4'-thio-bis(2-tertiary butyl-5-methyl-phenyl))isooctyl phosphite, mono(4,4'-thio-bis(2-tertiary-butyl-5-methyl phenol))di-phenyl phosphite, tri-(4,4'-n-butylidene-bis(2-tertiary-butyl-5-methylphenol))phosphite, (4,4'-benzylidene-bis(2-tertiary-butyl-5-methyl phenol))diphenyl phosphite, isooctyl 2,2'-bis(-parahydroxyphenyl)propane phosphite, decyl 4,4'-n-butylidene-bis(2-tertiary-butyl-5-methylphenol)phosphite, tri-4,4'-thio-bis(2-tertiary-butyl-5-methylphenol)phosphite, 2-ethylhexyl-2,2'-methylene-bis(4-methyl-6,1'-methylcyclohexyl)phenol phosphite, tri(2,2'-bis(para-hydroxyphenyl)propane)phosphite, tri(4,4'-thio-bis(2-tertiary-butyl-5-methyl-phenol)phosphite, isooctyl-(2,6-bis(2'-hydroxy-3,5-dinonylbenzyl)-4-nonyl phenyl))phosphite, tetra-tridecyl 4,4'-n-butylidene-bis(2-tertiary butyl-5-methyl phenyl)diphosphite, tetra-issoctyl 4,4'-thio-bis(2-tertiary butyl-5-methyl phenyl)diphosphite, 2,2'-methylene-bis(4-methyl 6,1'-methyl cyclohexyl phenyl)polyphosphite, isooctyl-4,4'-isopropylidene-bis-phenyl-polyphosphite, 2-ethylhexyl-2,2'-methylene-bis(4-methyl-6,1'-methyl-cyclohexyl)phenyl triphosphite, tetra-tridecyl-4,4'-oxydiphenyl diphosphite, tetra-n-dodecyl-4,4'-n-butylidene bis(2-tertiary-butyl-5-methylphenyl)diphosphite, tetra-tridecyl-4,4'-iso-propylidene bisphenyl diphosphite, hexa-tridecyl butane-1,1,3-tris(2'-methyl-5'-tertiary-butylphenyl-4'-)triphosphite.

Exemplary acid phosphite are di(phenyl)phosphite, monophenyl phosphite, mono-(diphenyl)phosphite, dicresyl phosphite, di-o-(isooctylphenyl)phosphite, di(p-ethylhexylphenyl)phosphite, di(p-t-octylphenyl)phosphite, di(dimethylphenyl)phosphite, di-n-butyl phosphite, di-2-ethylhexyl phosphite, mono-2-ethylhexyl phosphite, diisooctyl phosphite, monoisooctyl phosphite, monododecyl phosphite, 2-ethylhexyl phenyl phosphite, 2-ethylhexyl-(n-octylphenyl)phosphite, monocyclohexyl phosphite, dicyclohexyl phosphite, di(2-cyclohexyl phenyl)phosphite, di-α-naphthyl phosphite, diphenyl phenyl phosphite, di(diphenyl) phosphite, di-(2-phenyl ethyl)phosphite, dibenzyl phosphite, monobenzyl phosphite, n-butyl cresyl phosphite and didodecyl phosphite, cresyl phosphite, t-octylphenyl phosphite, ethylene phosphite, butyl cresyl phosphite, isooctyl monotolyl phosphite and phenyl cyclohexyl phosphite.

Exemplary of the bis aryl acid phosphites are: bis(4,4'-thio-bis(2-tertiary-butyl-5-methyl-phenol))phosphite, (4,4'-thiobis(2-tertiary-butyl-5-methyl-phenol))phenyl phosphite, bis(4,4'-n-butylidene-bis(2-tertiary-butyl-5-methyl-phenol))phosphite, mono(4,4'-benzylidene-bis(2-tertiary-butyl-5-methyl-phenol))phosphite, mono(2,2'-bis-(parahydroxyphenyl)propane)phosphite, mono(4,4'-n-butylidene-bis(2-tertiary-butyl-5-methyl-phenol)phosphite, bis(4,4'-thio-bis(2-tertiary-butyl-5-methylphenol))phosphite, mono-2-ethylhexyl-mono-2,2'methylene-bis(4-methyl-6,1'methylcyclohexyl)phenol phosphite, bis(2,2'-bis-(parahydroxyphenyl)propane)phosphite, monoisooctyl mono(4,4'-thiobis(2-tertiary-butyl-5-methyl-phenol))phosphite, isooctyl-(2,6-bis(2'-hydroxy-3,5-dinonylbenzyl)-4-nonyl phenyl))phosphite, tri-tridecyl 4,4'-n-butylidene-bis(2-tertiary-butyl-5-methyl phenyl)diphosphite, triisooctyl 4,4'-thio-bis(2-tertiary-butyl-5-methyl phenyl)diphosphite, bis(2,2'-methylene-bis(4-methyl-6,1'-methyl cyclohexyl phenyl))phosphite, isooctyl-4,4'-isopropylidene-bis-phenyl phosphite, monophenyl mono(2,2'-methylene-bis-(4-methyl-6,1'-methyl-cyclohexyl))triphosphite, di-tridecyl-4,4'-oxydiphenyl diphosphite, di-n-dodecyl-4,4'-n-butylidene bis(2-tertiary-butyl-5-methylphenyl)diphosphite, di-tridecyl-4,4'-isopropylidene bisphenyl diphosphite, tetra-tridecyl butane-1,3,3-tris(2'-methyl-5'-tertiary-butylphenyl-4-)triphosphite.

The phenolic antioxidant contains one or more phenolic hydroxyl groups, and one or more phenolic nuclei, and can contain from about eight to about three hundred carbon atoms. In addition, the phenolic nucleus can contain an oxy or thio ether group.

The alkyl-substituted phenols and polynuclear phenols, because of their molecular weight, have a higher boiling point, and therefore are preferred because of their lower volatility. There can be one or a plurality of alkyl groups of one or more carbon atoms. The alkyl group or groups including any alkylene groups between phenol nuclei preferably aggregate at least four carbon atoms. The longer the alkyl or alkylene chain, the better the compatability with polypropylene, inasmuch as the phenolic compound then acquires more of an aliphatic hydrocarbon character, and therefore there is no upper limit on the number of alkyl carbon atoms. Usually, from the standpoint of availability, the compound will not have more than about eighteen carbon atoms in an alkyl, alicyclidene and alkylene group, and a total of not over about fifty carbon atoms. The compounds may have from one to four alkyl radicals per phenol nucleus.

The phenol contains at least one and preferably at least two phenolic hydroxyls, the two or more hydroxyls being in the same ring, if there is only one. In the case of bicyclic phenols, the rings can be linked by thio or oxyether groups, or by alkylene, alicyclidene or arylidene groups.

The monocyclic phenols which can be employed have the structure: ##STR17## R is selected from the group consisting of hydrogen; halogen; and organic radicals containing from one to about thirty carbon atoms, such as alkyl, aryl, alkenyl, alkaryl, aralkyl, cycloalkenyl, cycloalkyl, alkoxy, and ##STR18## where R' is aryl, alkyl or cycloalkyl; x₁ and x₂ are integers from one to four, and the sum of x₁ and x₂ does not exceed six.

The polycyclic phenol employed in the stabilizer combination is one having at least two aromatic nuclei linked by a polyvalent linking radical, as defined by the formula: ##STR19## wherein Y is a polyvalent linking group selected from the group consisting of oxygen; carbonyl; sulfur; sulfinyl; aromatic, aliphatic and cycloaliphatic hydrocarbon groups; and oxyhydrocarbon, thiohydrocarbon and heterocyclic groups. The linking group can have from one up to twenty carbon atoms.

Ar is a phenolic nucleus which can be a phenyl or a polycarbocyclic group having condensed or separate phenyl rings; each Ar group contains at least one free phenolic hydroxyl group up to a total of five. The Ar rings can also include additional rings connected by additional linking nuclei of the type Y, for example, Ar--Y--Ar--Y--Ar.

m₁ and m₂ are numbers from one to five, and n₁ and n₂ are numbers of one or greater, and preferably from one to four.

The aromatic nucleus Ar can, in addition to phenolic hydroxyl groups, include onr or more inert substituents. Examples of such inert substituents include hydrogen, halogen atoms, e.g., chlorine, bromine and fluorine; organic radicals containing from one to about thirty carbon atoms, such as alkyl, aryl, alkaryl, aralkyl, cycloalkenyl, cycloalkyl, alkoxy, aryloxy and ##STR20## where R' is aryl, alkyl or cycloalkyl, or thiohydrocarbon groups having from one to about thirty carbon atoms, and ##STR21## Usually, however, each aromatic nucleus will not have more than about eighteen carbon atoms in any hydrocarbon substituent group. The Ar group can have from one to four substituent groups per nucleus.

Typical aromatic nuclei include phenyl, naphthyl, phenanthryl, triphenylenyl, anthracenyl, pyrenyl, chrysenyl, and fluorenyl groups.

When Ar is a benzene nucleus, the polyhydric polycyclic phenol has the structure: ##STR22## wherein R₁, R₂ and R₃ are inert substituent groups as described in the previous paragraph;

m₁ and m₃ are integers from one to a maximum of five;

m₂ is an integer from one to a maximum of four;

x₁ and x₃ are integers from zero to four; and

x₂ is an integer from zero to three;

y₁ is an integer from zero to six; and

y₂ is an integer from one to five, preferably one or two.

Preferably, the hydroxyl groups are located ortho and/or para to Y.

Exemplary Y groups are alkylene, alkylidene, and alkenylene arylene, alkylarylene, arylalkylene, cycloalkylene, cycloalkylidene, and oxa- and thia-substituted such groups; carbonyl groups, tetrahydrofuranes, esters and triazino groups. The Y groups are usually bi, tri, or tetravalent, connecting two, three or four Ar groups. However, higher valency Y groups, connecting more than four Ar groups can also be used. According to their constitution, the Y groups can be assigned to subgenera as follows:

(1) Y groups where at least one carbon in a chain or cyclic arrangement connect the aromatic groups, such as: ##STR23##

(2) Y groups where only atoms other than carbon link the aromatic rings, such as: --O--, --S--, ##STR24## and --(S)_(x) -- where x is a number from one to ten;

(3) Y groups made up of more than a single atom including both carbon and other atoms linking the aromatic nuclei, such as: ##STR25##

Although the relation of effectiveness to chemical structure is insufficiently understood, many of the most effective phenols have Y groups of subgenus (1), and accordingly this is preferred. Some of these phenols can be prepared by the alkylation of phenols or alkyl phenols with polyunsaturated hydrocarbons such as dicyclopentadiene or butadiene.

Representative phenols include guaiacol, resorcinol monoacetate, vanillin, butyl salicylate, 2,6-di-tert-butyl-4-methyl phenol, 2-tert-butyl-4-methoxy phenol, 2,4-dinonyl phenol, 2,3,4,5-tetradecyl phenol, tetrahydro-α-naphthol, o-, m- and p-cresol, o-, m- and p-phenylphenol, o-, m- and p-xylenols, the carvenols, symmetrical xylenol, thymol, o-, m- and p-nonylphenol, o-, m- and p-dodecyl-phenol, and o-, m- and p-octyl phenol, o-, and m-tert-butyl-p-hydroxy-anisole, p-n-decyloxy-phenol, p-n-decyloxycresol, nonyl-n-decyloxy-cresol, eugenol, isoeugenol, glyceryl monosalicylate, methyl-p-hydroxy-cinnamate, 4-benzyloxy-phenol, p-acetylaminophenol, p-stearyl-aminophenol methyl-p-hydroxy benzoate, p-di-chlorobenzoyl-aminophenol, p-hydroxysalicyl anilide, stearyl-(3,5-di-methyl-4-hydroxy-benzyl)thioglycolate, stearyl-β-(4-hydroxy-3,5-di-t-butylphenyl)priopionate, distearyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate, and distearyl (4-hydroxy-3-methyl-5-t-butyl)benzylmalonate.

Exemplary polyhydric phenols are orcinol, propyl gallate, catechol, resorcinol, 4-octyl-resorcinol, 4-dodecyl-resorcinol, 4-octadecyl-catechol, 4-isooctyl-phloroglucinol, pyrogallol, hexahydroxybenzene, 4-isohexylcatechol, 2,6-di-tertiary-butylresorcinol, 2,6-di-isopropyl-phloroglucinol.

Exemplary polyhydric polycyclic phenols are methylene bis-(2,6-di-tertiary-butyl-phenol), 2,2-bis-(4-hydroxy phenyl)propane, methylene-bis-(p-cresol), 4,4'-benzylidene bis-(2-tertiary-butyl-5-methyl-phenol), 4,4'-cyclohexylidene bis-(2-tertiary-butylphenol), 2,2'-methylene-bis-(4-methyl-6-(1'-methyl-cyclohexyl)-phenol), 2,6-bis(2'-hydroxy-3'-tertirary-butyl-5'-methylbenzyl)-4-methylphenol, 4,4'-bis-(2-tertiary-butyl-5-methyl-phenol), 2,2'-bis-(4-hydroxy-phenyl)butane, ethylene bis-(p-cresol), 4,4'-oxobis-phenol, 4,4'-oxobis(3-methyl-5-isopropylphenol), 4,4'-oxobis-(3-methyl-phenol), 2,2'-oxobis-(4-dodecylphenol), 2,2'-oxobis-(4-methyl-5-tertiary-butyl-phenol), 4,4'-thio-bis-phenol; 4,4'-thio-bis-(3-methyl-6-tertiary-butyl-phenol), 2,2'-thio-bis-(4-methyl-6-tertiary-butyl-phenol), 4,4'-n-butylidene-(2-t-butyl-5-methyl-phenol), 2,2'-methylene-bis-(4-methyl-6-(1'-methyl-cyclohexyl)-phenol), 4,4'-cyclohexylene bis(2-tertiary-butyl-phenol), 2,6-bis-(2'-hydroxy-3'-t-butyl-5'-methyl-benzyl)-4-methyl-phenol, 4,4'-oxobis(naphthalene-1,5-diol), 1,3'-bis-(naphthalene-2,5-diol)propane, and 2,2'-butylene bis-(naphthalene-2,7-diol), (3-methyl-5-tert-butyl-4-hydroxyphenyl)-4'-hydroxy-phenyl propane, 2,2' -methylene-bis-(4-methyl-5-isopropylphenol), 2,2'-methylene bis-(5-tert-butyl-4-chlorophenol), (3,5-di-tert-butyl-4-hydroxyphenyl)-(4'-hydroxy-phenyl)ethane, (2-hydroxy-phenyl)-(3',5'-di-tert-butyl-4',4-hydroxyphenyl)ethane, 2,2'-methylene bis-(4-octylphenol), 4,4'-propylene bis-(2-tert-butyl-phenol), 2,2'-isobutylene bis-(4-nonylphenol), 2,4-bis-(4-hydroxy-3-t-butyl-phenoxy)-6-(n-octylthio)-1,3,5-triazine, 2,4,6-tris-(4-hydroxy-3-t-butyl-phenoxy)-1,3,5-triazine, 2,2'-bis-(3-t-butyl-4-hydroxyphenyl)thiazolo-(5,4-d)thiazole, 2,2'-bis-(3-methyl-5-t-butyl-4-hydroxyphenyl)thiazolo-(5,4-d)-thiazole, 4,4'-bis-(4-hydroxy-phenyl)pentanoic acid octadecyl ester, cyclopentylene-4,4'-bis-phenol, 2-ethylbutylene-4,4'-bisphenol, 4,4'-cyclooctylene-bis-(2-cyclohexylphenol), β,β-thiodiethanol bis-(3-tert-butyl-4-hydroxyphenoxy acetate), 1,4-butanedio bis-(3-tert-butyl-4-hydroxyphenoxy acetate), pentaerythritoltetra(4-hydroxyphenol propionate), 2,4,4'-tri-hydroxy benzophenone, bis-(2-tert-butyl-3-hydroxy-5-methylphenyl)sulfide, bis-(2-tert-butyl-4-hydroxy-5-methylphenyl)sulfide, bis-(2-tert-butyl-4-hydroxy-5-methyl-phenyl sulfoxide), bis-(3-ethyl-5-tert-butyl-4-hydroxy benzyl)sulfide, bis-(2-hydroxy-4-methyl-6-tert-butyl phenyl)sulfide, 4,4'-bis-(4-hydroxy-phenol)pentanoic acid octadecyl thiopropionate ester, 1,1,3-tris-(2'-methyl-4-hydroxy-5'-tert-butylphenyl)butane, 1,1,3-tris-(1-methyl-3-hydroxy-4-tert-butylphenyl)butane, 1,8-bis-(2-hydroxy-5-methylbenzoyl-n-octane, 2,2'-ethylene-bis-[4'-(3 -tert-butyl-4-hydroxyphenyl)thiazole], 1-methyl-3-(3-methyl-5-tert-butyl-4-hydroxybenzyl)-naphthalene, 2,2'-(2-butene)-bis-(4-methoxy-6-tert-butyl phenol)-bis-[3,3-bis-(4-hydroxy-3-t-butylphenyl)butyric acid]glycol ester, 4,4'-butylidene-bis-(6-t-butyl-m-cresol), 1,1,3-tris-(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane, 1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris-(3,5-di-t-butyl-4-hydroxyphenyl)propionyl-oxyethyl isocyanurate, 2-octylthio-4,6-di-(4-hydroxy-3,5-di-t-butyl)phenoxy-1,3,5-triazine, 4,4'-thiobis(6-t-butyl-m-cresol) and pentaerythritol hydroxyphenyl propionate.

A particularly desirable class of polyhydric polycyclic phenols are the dicyclopentadiene polyphenols, which are of the type: ##STR26## in which R₁ and R₂ are lower alkyl, and can be the same or different, and

n is the number of the groups enclosed by the brackets, and is usually from 1 to about 5. These are described in U.S. Pat. No. 3,567,683, dated Mar. 2, 1971 to Spacht. A commercially available member of this class is Wingstay L, exemplified by dicyclopentadiene tri-(2-tert-butyl-4-methyl-phenol) of the formula: ##STR27##

The polyhydric polycyclic phenols used in the invention can also be condensation products of phenol or alkylphenols with hydrocarbons having a bicyclic ring structure and a double bond or two or more double bonds, such as α-pinene, β-pinene, dipentene, limonene, vinylcyclohexene, dicyclopentadiene, allo-ocimene, isoprene and butadiene. These condensation products are usually obtained under acidic conditions in the form of more or less complex mixtures of monomeric and polymeric compounds. However, it is usually not necessary to isolate the individual constituents. The entire reaction product, merely freed from the acidic condensation catalyst and unchanged starting material, can be used with excellent results. While the exact structure of these phenolic condensation products is uncertain, the Y groups linking the phenolic nuclei all fall into the preferred subgenus (1). For method of preparation, see e.g., U.S. Pat. Nos. 3,124,555, 3,242,135 and British Pat. No. 961,504.

Oxirane or 1,2-epoxide stabilizers can be included with the stabilizers of this invention in amounts within the range from about 0.01 to about 10 parts by weight per 100 parts by weight of polymer. Typical 1,2-epoxide stabilizers are epoxidized polybutadiene, epoxy soybean oil, epoxy linseed oil, epoxy fish oil, epoxy tallow, methyl-butyl or 2-ethylhexylepoxy stearate, tris(epoxypropyl)isocyanurate, epoxy castor oil, epoxy safflower oil, 3-(2-xenoxy)-1,2-epoxy propane, Bisphenol A.polyglycidyl ether, vinyl cyclohexene diepoxide, dicyclopentadiene diepoxide and 3,4-epoxy cyclohexylmethyl-3,4-epoxy cyclohexane carboxylate.

Polyols can be employed with the stabilizer compositions in amounts within the range from about 0.01 to about 3 parts by weight per 100 parts by weight of resin. Typical polyols are pentaerythritol, dipentaerythritol, trimethylol propane, ditrimethylolpropane, tris(2-hydroxyethyl)isocyanurate, sorbitol, mannitol and inositol.

In addition, any other conventional polyvinyl halide resin additives, such as lubricants, emulsifiers, antistatic agents, flame-proofing agents, pigments and fillers, can be employed.

The stabilizer system is incorporated in the polymer in suitable mixing equipment, such as a mill or a Banbury mixer. If the polymer has a melt viscosity which is too high for the desired use, the polymer can be worked until its melt viscosity has been reduced to the desired range before addition of the stabilizer. Mixing is continued until the mixture is substantially uniform. The resulting composition is then removed from the mixing equipment and brought to the size and shape desired for marketing or use.

The stabilized polyvinyl halide resin can be worked into the desired shape, such as by milling, calendering, extrusion or injection molding, or fiber-forming. In such operations, it will be found to have a considerably improved resistance to discoloration and embrittlement on exlposure to heat and light.

The following Examples illustrate preferred stabilizer systems and resin compositions of the invention:

EXAMPLES 1 TO 9

A group of polyvinyl chloride resin compositions was prepared having the following formulation:

    ______________________________________                                         Ingredients            Parts by Weight                                         ______________________________________                                         Polyvinyl chloride homopolymer                                                                        100                                                     Dioctyl phthalate      50                                                      CaCO.sub.3             20                                                      Zn stearate            0.3                                                     Ba stearate            0.7                                                     Mg.sub.0.7 Al.sub.0.3 (OH).sub.2 (CO.sub.3).sub.0.15 O.57H.sub.2 O                                    0.5                                                     β-Diketone compound shown in Table I                                                             0.1                                                     ______________________________________                                    

This formulation was blended and sheeted off on a two-roll mill to form sheets 1 mm thick.

The sheets were heated in air in a Geer oven at 190° C. to evaluate heat stability, and the time in minutes noted for the sheet to develop a noticeable discoloration and/or embrittlement, reported in the Table below as time to failure. Initial color was also noted, as well as volume resistivity (VR) according to ASTM D-257-66.

The results are shown in Table I.

                                      TABLE I                                      __________________________________________________________________________                             Time to                                                                  VR    Failure at                                             Example           (Ω · cm)                                                              190° C.                                         No.   β-Diketone Compound                                                                   × 10.sup.13                                                                    (minutes)                                                                            Initial Color                                    __________________________________________________________________________     Control 1                                                                            None.sup.1  3.17  120   Very                                                                           inferior                                         Control 2                                                                            Octyl acetoacetate                                                                         0.87  120   Inferior                                         Control 3                                                                            Ba stearate 0.5                                                                            1.20   90   Medium                                                 (without hydrotalcite)                                                   Control 4                                                                            Dibenzoylmethane.sup.2                                                                     0.53   75   Medium                                           1     Dibenzoylmethane                                                                           6.92  180   Very good                                        2     Stearoylbenzoyl-                                                                           6.48  180   Very good                                              methane                                                                  3     Benzoylacetone                                                                             5.03  150   Good                                             4     Bis-(p-t-butylbenzoyl)                                                                     6.20  165   Good                                                   methane                                                                  5     Benzoyl-3-carbo                                                                            5.36  180   Very good                                              methoxy-benzoyl                                                                methane                                                                  6     Zn salt of dibenzoyl-                                                                      6.88  180   Very good                                              methane                                                                  7     Ba salt of dibenzoyl-                                                                      6.15  180   Very good                                              methane                                                                  8     Zn salt of stearoyl-                                                                       6.39  180   Very good                                              benzoylmethane                                                           9     Zn salt of dehydro-                                                                        4.74  150   Good                                                   acetic acid                                                              __________________________________________________________________________      .sup.1 With 0.6 hydrotalcite instead of 0.5.                                   .sup.2 With 0.6 dibenzoylmethane instead of 0.1 (without hydrotalcite).  

The improvement compared with the Controls is evident from the data.

It is apparent that hydrotalcite as a class are effective.

EXAMPLES 10 TO 14

A group of polyvinyl chloride resin compositions was prepared having the following formulation:

    ______________________________________                                         Ingredients         Parts by Weight                                            ______________________________________                                         Polyvinyl chloride homopolymer                                                                     100                                                        Dioctyl phthalate   50                                                         CaCO.sub.3          20                                                         Ca stearate         0.5                                                        Zn stearate         0.5                                                        Dibenzoyl methane   0.05                                                       Bisphenol A         0.1                                                        Hydrotalcite shown in Table II                                                                     0.3                                                        ______________________________________                                    

This formulation was blended and sheeted off on a two-roll mill to form sheets 1 mm thick.

The sheets were heated in air in a Geer oven at 190° C. to evaluate heat stability, and the time in minutes noted for the sheet to develop a noticeable discoloration and/or embrittlement, reported as time to failure in Table II. Initial color was also noted and volume resistivity (VR) was also measured using the test described in Examples 1 to 9.

The results are shown in Table II.

                                      TABLE II                                     __________________________________________________________________________                                  Time to                                                                   VR   Failure at                                                                (Ω · cm)                                                             190° C.                                    Example No.                                                                           Hydrotalcite     × 10.sup.12                                                                   (minutes)                                                                            Initial Color                               __________________________________________________________________________     Control 1                                                                             None.sup.1       0.796                                                                               30    Good                                        Control 2                                                                             Mg.sub.0.7 Al.sub.0.3 (OH).sub.2 (CO.sub.3).sub.0.15 0.57H.sub.2                                5.23 75    Very inferior                                      (without dibenzoylmethane)                                              Control 3                                                                             MgO              2.16 60    Inferior                                    Control 4                                                                             Mg.sub.0.7 Al.sub.0.3 (OH).sub.2 (CO.sub.3).sub.0.15 0.57H.sub.2               O.sup.2          5.37 75    Very inferior                               10     Mg.sub.0.7 Al.sub.0.3 (OH).sub.2 (CO.sub.3).sub.0.15 0.57H.sub.2                                11.0 130   Very good                                   11     Mg.sub.0.8 Al.sub.0.2 (OH).sub.2 (CO.sub.3).sub.0.1 0.61H.sub.2                                 9.27 130   Very good                                   12     Mg.sub.0.75 Al.sub.0.25 (OH).sub.2 (CO.sub.3).sub.0.125 0.5H.sub.2             O                9.01 105   Good                                        13     Mg.sub.0.6 Al.sub.0.4 (OH).sub.2 (CO.sub.3).sub.0.2 0.48H.sub.2                                 10.2 130   Very good                                   14     Mg.sub.0.75 Al.sub.0.25 (OH).sub.2 (SO.sub.4).sub.0.125 0.5H.sub.2             O                8.55 90    Good                                        __________________________________________________________________________      .sup.1 With 0.35 dibenzoylmethane instead of 0.05.                             .sup.2 With 0.35 hydrotalcite instead of 0.3 (without dibenzoyl methane).

EXAMPLES 15 TO 22

A group of polyvinyl chloride resin compositions was prepared having the following formulation:

    ______________________________________                                         Ingredients           Parts by Weight                                          ______________________________________                                         Polyvinyl chloride homopolymer                                                                       100                                                      Dioctyl phthalate     50                                                       Zn stearate           0.3                                                      Ba stearate           0.7                                                      Mg.sub.0.7 Al.sub.0.3 (OH).sub.2 (CO.sub.3).sub.0.15 0.57H.sub.2 O                                   1.0                                                      β-Diketone compound shown in Table III                                                          0.05                                                     ______________________________________                                    

This formulation was blended and sheeted off on a two-roll mill to form sheets 1 mm thick.

The sheets were heated in air in a Geer oven at 190° C. to evaluate heat stability, and the time in minutes noted for the sheet to develop a noticeable discoloration and/or embrittlement, reported as time to failure in Table III. Initial color was also observed. Volume resistivity (VR) was also measured using the test of Examples 1 to 9.

The results are shown in Table III.

                                      TABLE III                                    __________________________________________________________________________                             Time to                                                                  VR    Failure at                                             Example           (Ω · cm)                                                              190° C.                                         No.   β-Diketone Compound                                                                   × 10.sup.13                                                                    (minutes)                                                                            Initial Color                                    __________________________________________________________________________     Control 1                                                                            None (without hydro-                                                                       0.84   30   Medium                                                 talcite and β-diketone)                                             Control 2                                                                            None        2.84   75   Very                                                                           inferior                                         Control 3                                                                            Octyl acetoacetate                                                                          0.259                                                                                90   Slightly                                                                       inferior                                         Control 4                                                                            None.sup.1  2.96   75   Very                                                                           inferior                                         Control 5                                                                            Dibenzoylmethane.sup.2                                                                     0.63   45   Slightly                                               (without hydrotalcity)  good                                             15    Dibenzoylmethane                                                                           6.27  150   Very good                                        16    Benzoyl acetone                                                                            5.40  135   Good                                             17    Palmitoylbenzoyl-                                                                          5.93  150   Very good                                              methane                                                                  18    Stearoylbenzoyl-                                                                           6.14  150   Very good                                              methane                                                                  19    2-Benzoylcyclo-                                                                            5.74  135   Good                                                   hexanone                                                                 20    Zn salt of dibenzoyl-                                                                      6.08  150   Very good                                              methane                                                                  21    Ca salt of dibenzoyl-                                                                      5.85  150   Very good                                              methane                                                                  22    Zn salt of stearoyl-                                                                       5.80  150   Very good                                              benzoylmethane                                                           It is apparent that β-diketones as a class are effective.                 __________________________________________________________________________      .sup.1 With 1.05 hydrotalcite instead of 1.0.                                  .sup.2 With 1.05 dibenzoylmethane instead of 0.05.                       

EXAMPLES 23 TO 30

A group of polyvinyl chloride resin compositions was prepared having the following formulation:

    ______________________________________                                         Ingredients          Parts by Weight                                           ______________________________________                                         Polyvinyl chloride homopolymer                                                                      100                                                       Dioctyl phthalate    50                                                        CaCO.sub.3           20                                                        Zn stearate          0.3                                                       Ba stearate          0.7                                                       Mg.sub.0.7 Al.sub.0.3 (OH).sub.2 (CO.sub.3).sub.0.15 0.57H.sub.2 O                                  0.5                                                       Dibenzoyl methane    0.05                                                      Additional stabilizer shown in Table IV                                                             Amount shown in                                                                Table IV                                                  ______________________________________                                    

This formulation was blended and sheeted off on a two-roll mill to form sheets 1 mm thick.

The sheets were heated in air in a Geer oven at 190° C. to evaluate heat stability, and the time in minutes noted for the sheet to develop a noticeable discoloration and/or embrittlement, reported in Table IV as time to failure. Initial color was also observed. Volume resistivity (VR) was also measured using the test of Examples 1 to 9.

The results are shown in Table IV.

                                      TABLE IV                                     __________________________________________________________________________                                        Time to                                                                   VR   Failure at                                                                (Ω · cm)                                                             190° C.                              Example No.                                                                           Additional Stabilizer                                                                            Amount                                                                              × 10.sup.13                                                                   (minutes)                                                                            Initial Color                         __________________________________________________________________________     Control 1                                                                             None (without dibenzoylmethane)                                                                       3.17 120   Very inferior                         Control 2                                                                             Dipentaerythritol (without dibenzoyl-                                                            0.5  2.06 135   Inferior                                     methane)                                                                Control 3                                                                             Tris-nonylphenyl phosphite (without                                                                   2.13 135   Inferior                                     dibenzoylmethane)                                                       23     None                   5.95 150   Good                                  24     Dipentaerythritol 0.5  5.82 <180  Very good                             25     Tris-(2-hydroxyethyl) isocyanuarate                                                              0.5  5.26 180   Very good                             26     Sorbitol          0.5  5.54 <180  Very good                             27     Tris-nonylphenylphosphite                                                                        0.2  5.32 180   Very good                             28     Octyl diphenylphosphite                                                                          0.2  5.07 180   Very good                             29     Phenyl-Bisphenol A-pentaerythritol                                                               0.2  5.87 <180  Very good                                    diphosphite                                                             30     Tetra-(C.sub.12-15 alkyl).Bis-phenol A                                                           0.2  5.48 <180  Very good                                    diphosphite                                                             __________________________________________________________________________

It is apparent that with an additional stabilizer, a further enhanced effect is obtained. 

Having regard to the foregoing disclosure, the following is claimed as the patentable and inventive embodiments thereof:
 1. A stabilizer composition for halogen-containing polymers are provided composed of at least one member of the group consisting of β-diketones having the formula: ##STR28## wherein: R₁ is selected from the group consisting of hydrogen, hydrocarbon groups having from one to about eighteen carbon atoms and such groups substituted with one or more groups selected from the group consisting of halogen, hydroxy, alkoxy OR₁, ester COOR₁, alkyl and alkoxycarbonyl alkyl having from one to about eighteen carbon atoms, and ##STR29## R₂ is selected from the group consisting of hydrogen; hydroxyl; hydrocarbon having from one to about eighteen carbon atoms and such hydrocarbon groups substituted with one or more groups selected from the group consisting of halogen, hydroxy, alkoxy OR₁, ester COOR₁, alkyl and alkoxycarbonyl having from one to about eighteen carbon atoms; but if Z is R₂ or n is 1 to 3, then no more than one R₂ is hydrogen;one R₁ and one R₂ or two R₂ may be linked together as an alkylene group to form a cyclic or ring structure; n is a number from 0 to 3; and Z is selected from the group consisting of R₂ and a polyvalent linking radical selected from the group consisting of a direct linkage between the ##STR30## polyvalent hydrocarbon R₃ ; ##STR31## wherein: R₃ is a polyvalent hydrocarbon group having from one to about eighteen carbon atoms; R₄ and R₅ are selected from the group consisting of hydrogen and hydrocarbon groups having from one to about eighteen carbon atoms; and R₄ and R₅ may be linked together as an alkylene to form a cyclic or ring structure; X is --O-- or --S--; m is 0 or 1; and R₆ is selected from the group consisting of hydrogen, hydrocarbon having from one to about eighteen carbon atoms, and --R₃ --;and metal and organotin enolate salts thereof; and a hydrotalcite having the general formula:

    Mg.sub.1-x Al.sub.x (OH).sub.2 A.sub.x/2.m.sub.1 H.sub.2 O

wherein x is a number from 0 to 0.5; A is CO₃ ⁼ or SO₄ ⁼, and m₁ is a number representing the number of H₂ O in the molecule.
 2. A stabilizer composition according to claim 1 in which the β-diketone is in ketone form.
 3. A stabilizer composition according to claim 1 in which the β-ketone is in the form of a metal enolate salt.
 4. A stabilizer composition according to claim 3 in which the metal is an alkali or alkaline earth metal.
 5. A stbilizer composition according to claim 3 in which the metal is a polyvalent metal.
 6. A stabilizer composition according to claim 3 i which the metal is selected from the group consisting of lithium, sodium, potassium magnesium, strontium calcium, barium, cadmium, lead, zinc, tin, aluminum, antimony and zirconium.
 7. A stabilizer composition according to claim 3 in which the metal salt is an organotin enolate salt.
 8. A stabilizer composition according to claim 7 in which the organotin is (R)_(n).sbsb.1 Sn, wherein n₁ is a number from 1 to 3 and R is a hydrocarbon group having from one to about eighteen carbon atoms.
 9. A stabilizer composition according to claim 8 in which n₁ is
 1. 10. A stabilizer composition according to claim 8 in which n₁ is
 2. 11. A stabilizer composition according to claim 8 in which n₁ is
 3. 12. A stabilizer composition according to claim 1 in which both R₁ are hydrogen.
 13. A stabilizer composition according to claim 1 in which one R₁ is hydrogen and the other is ##STR32##
 14. A stabilizer composition according to claim 1 in which R₂ is alkyl.
 15. A stabilizer composition according to claim 1 in which R₂ is aryl.
 16. A stabilizer composition according to claim 15 in which R₂ is selected from the group consisting of phenyl, alkyl phenyl, alkoxy phenyl, and halophenyl.
 17. A stabilizer composition according to claim 1 in which two R₃ or one R₁ and one R₂ are taken together to form cycloalkyl.
 18. A stabilizer composition according to claim 1 in which Z is R₂ and n is zero.
 19. A stabilizer composition according to claim 18 in which the Z R₂ is an alkyl group having from one to about eighteen carbon atoms.
 20. A stabilizer composition according to claim 18 in which the Z R₂ is an aryl group.
 21. A stabilizer composition according to claim 18 in which the Z R₂ is OH.
 22. A stabilizer composition according to claim 1 in which the hydrotalcite is represented by the formula:

    Mg.sub.0.7 Al.sub.0.3 (OH).sub.2 (CO.sub.3).sub.0.5 0.57H.sub.2 O.


23. A stabilizer composition according to claim 1 in which the hydrotalcite is represented by the formula:

    Mg.sub.0.8 Al.sub.0.2 (OH).sub.2 (CO.sub.3).sub.0.1.0.61H.sub.2 O.


24. A stabilizer composition according to claim 1 in which the hydrotalcite is represented by the formula:

    Mg.sub.0.6 Al.sub.0.4 (OH).sub.2 (CO.sub.3).sub.0.2 0.48H.sub.2 O.


25. A polyvinyl halide resin composition having improved resistance to deterioration when heated at 350° F., comprising a polyvinyl halide resin formed at least in part of the recurring group: ##STR33## and having a halogen content in excess of 40%, where X₁ is halogen and X₂ is either hydrogen or halogen and a stabilizer composition according to claim
 1. 26. A polyvinyl halide resin composition in accordance with claim 25 in which the polyvinyl halide resin is polyvinyl chloride homopolymer.
 27. A polyvinyl halide resin composition in accordance with claim 25 in which the polyvinyl halide resin is a copolymer of vinyl chloride and a copolymerizable monomer.
 28. A polyvinyl halide resin composition in accordance with claim 27 in which the copolymerizable monomer is vinyl acetate. 